INSTRUMENTATION: There will be further development of a number of small devices such as: a) response time estimator for investigation of epileptic patients; b) the development of a comprehensive data processing system based on the LSI/11 processor which will undertake the generation of GSA's, Somnograms, and various types of near and far field evoked potentials. In addition, there will be studies in the following general areas: 1) Sleep. There will be further development of a device which allows an all night sleep recording to be carried out from the patient's home. This will involve the use of a Medilog recorder and play back into the PDP/11 computer; 2) Coma. Similar studies will be made in patients with coma with the addition of evoked potentials of brainstem and cortical origin to more clearly delineate the location of lesion-causing coma; 3) Epilepsy. Tests of the CSA and Comagram technique for detection of seizures occurring during the night will be carried out on epileptic patients in whom the diagnosis may not be clinically evident.